Today, integrated electronic circuits include many transistors, and it may be useful to know the performance parameters of the transistors to maintain an operational quality for the integrated circuits. Indeed, measuring the performance parameters of the transistors allows them to be sorted by performance ranges, or provides the ability to subsequently correct performance losses to optimize the operation of the integrated circuits.
It therefore may be useful to know the speed performance parameters of transistors, or in other words, the capacity of a transistor to conduct current when it is in the on state. In particular, as the majority of integrated circuits are fabricated with Complementary Metal Oxide Semiconductor (CMOS) transistors, it may be desirable to differentiate the performance parameters of the transistors of the p-MOS type (p-doped channel transistors) from those of the transistors of the n-MOS type (n-doped channel transistors). This is because the various types of CMOS transistors can exhibit different performance parameters within the same integrated circuit.
One type of circuit is the ring oscillator that includes inverters with two n-MOS and p-MOS transistors, and which may be well known to those skilled in the art, but these circuits do not allow the performance parameters of each type of transistor to be decorrelated.
In addition, the power consumption of a transistor is a strategic factor for users of integrated circuits inside systems operating with small energy storage units, such as mobile telephones, PDAs, etc. The power consumption of a transistor is mainly due to the leakage current flowing inside a transistor when it is powered and when it is in the steady state, or in other words, when it is held in the off or on state. It is therefore important to determine the power consumption of a transistor and, more particularly, in static operation when the latter is powered without being loaded to determine the power consumption of a system including several transistors.
In the following, a transistor is considered to be in the on state when it allows an electrical current to flow between its source and its drain, and to be in an off state when it does not allow an electrical current to flow between its source and its drain.
Currently, the power consumption of circuits is typically quantified by analysis of the discharge time through a large transistor. However, this technique may not adapt to the conditions of limited surface area. This is because typically the smaller the transistor, the longer the discharge time, and hence the longer the analysis of the power consumption of the transistors. Since the size of transistors continues to become smaller, the analysis of their power consumption shall be fast, of very limited size, and sufficiently precise. In addition, the current technique includes waiting for the complete discharge of a transistor, which can lead to a measurement that takes long to implement.
Furthermore, transistors may be the main elements of memory systems, such as Static Random Access Memory (SRAM), commonly referred to as volatile memory. The transistors equipping these SRAM systems are typically configured in a specific manner. In other words, each transistor may be placed within a particular environment.
To measure the performance parameters of a transistor that is included within an SRAM system, it may be placed within its specific environment. In other words, the elements that characterize an SRAM system may be recreated, and the transistor's performance parameters measured within this recreated SRAM system.